It’s a shocking story. Good Samaritan Hugo Tale-Yax was stabbed in the chest after saving a woman from being mugged – and then lay ignored on a busy New York street for more than an hour before he died.

CCTV footage shows that, in total, 25 people walked past as he bled to death. Some paused to look, one curious man lifted him slightly – and someone even stopped to take a picture – but not one person helped or called the emergency services.

So what’s going on here? Joe Mulligan, our head of first aid learning, has a good idea. He said: “This is a perfect example of the bystander effect, where people hope someone else will step in, and it’s something we have to address in first aid training.

“Actions taken by the first people on the scene can mean the difference between life and death – and that’s why we need to ensure not only that everyone knows some first aid but also that they have the confidence and willingness to use it.”

The picture with this tragic story is complicated slightly by the fact that Mr Tale-Yax – who unquestionably acted heroically – was also homeless. A recent Red Cross survey showed that 57 per cent of UK adults would be less likely to give first aid to someone if they appeared to be homeless, drunk or on drugs.

So as well as being part of a particularly vulnerable group, homeless people also have to contend with a higher probability that they’ll be ignored if in need. That’s why the Red Cross works with homeless projects across the UK, teaching first aid skills and demonstrating how to deal with conditions such as hypothermia and frostbite.

This is such a depressing story – and I can’t help thinking that if someone with a bit of basic first aid training had walked past, then the outcome might have been very different.